Novel epoxide resins prepared from alpha, alpha&#39;, alpha&#34;-tris(hydroxyphenyl)-1, 3, 5-triisopropylbenzene and 2, 2-bis(p-hydroxyphenyl)propane



United States Patent N OVEL EPOXIDE RESINS PREPARED FROM oc,ot',ot"- TRISG-IYDROXYPHENYL) 1,3,5 TRIISOPRO- PYLBENZENE AND 2,2 BIS(p-HYDROXYPHEN- YL)PROPANE Oliver A. Barton, Florham Park, and Ralph M. Hetterly,

Morristown, N.J., assignors to Allied Chemical Corporation, New York, N.Y., a corporation of New York No Drawing. Filed Aug. 18, 1965, Ser. No. 480,753

6 Claims. (Cl. 260-47) ABSTRACT 0F THE DISCLOSURE This specification discloses novel terpolymeric epoxides prepared by reacting a,e',a-tris(hydroxyphenyl)-l,3,5- triisopropylbenzene, 2,2 bis(p-hydroxyphenyl)propane, and epichlorohydrin in the presence of an alkali. When cured, the epoxides of the invention have surprisingly high heat distortion temperatures.

Epoxide resins and processes for their production by the reaction of dihydric phenols and epichlorohydrin in the presence of a condensing agent such as caustic soda are well known. Such resins vary in their physical state from liquids to semi-solids to solids and are generally cured to thermoset condition by heating in the presence of chemical hardening agents such as aromatic amines. Resins produced by such curing have a high molecular weight which renders them particularly suitable for use as coatings, adhesives, and laminates and for use as potting and encapsulating compositions. US. Patent 3,293,213 issued Dec. 20, 1966 to Barton and Schwartz assigned to this assignee, discloses new terpolymeric resins of the above-mentioned types, which have greater hardness and resistance to chemical attack, prepared by a process which includes the interaction of 1,4-bis(p-hydroxycumyl)benzene with an epoxide resin prepared from 2,2-bis(p-hydroxyphenyl)-propane and epichlorohydrin.

One property of cured epoxide resins which is extremely desirable and useful is a high heat distortion temperature with its attendant good resistance to solvents and electricity. This property is especially useful for heat resistant coatings and adhesives. High heat distortion temperatures will be realized in highly cross-linked cured resins of low molecular weight epoxides, wherein the proportion of reactive epoxide groups per gram of resin is large. This is measured as epoxide equivalent, which is defined as the weight of resin in grams that contains one gram equivalent of epoxy. When other conditions remain constant, i.e. curing agent and curing cycle, the heat distortion temperature in general increases with decreasing epoxide equivalent. This can be explained on the basis that as epoxide equivalent decreases, the proportion of reactive epoxide groups present per gram of resin through which crosslinking or curing occurs increases and correspondingly, the extent of cross-linking increases.

An advantage of low molecular weight epoxide resins is that they are liquid at room temperature and can be poured or allowed to flow into place without the need of solvents or heating. When employing highly reactive curing agents, an increase in temperature shortens the curing time so that it is diflicult to utilize the resin before it crosslinks to a solid material.

It is an object of this invention to provide new terpoly- 3,375,259 Patented Apr. 2, 1968 ice meric epoxide resins having high heat distortion temperatures when cured, and a process for producing them.

It is another object of this invention to provide new low molecular weight terpolymeric epoxide resins, and a process for producing them.

In accordance with this invention, low molecular weight tel-polymeric epoxide resins having surprisingly high heat distortion temperatures when cured may be prepared by the reaction of a,o',a"-tris(hydroxyphenyl)-l,3,5-triisopropylbenzene, 2,2 bis(p-hydroxyphenyl) propane and epichlorohydrin in liquid phase.

More particularly, the terpolymeric epoxide resins may be prepared by heating, at a temperature of about C. up to about reflux temperature, and preferably from about C. to about C., a reaction mixture comprising ago/,0:"-tIlSfllYdlOXYphGIlYl) 1,3,5 triisopropylbenzene, 2,2-bis(p-hydroxyphenyl)propane, and epichlorohydrin in the presence of an alkali.

The bisphenol and trisphenol are present in a molar ratio between about 0.5 :1 and about 2:1 of trisphenol to bisphenol. In order to prepare low molecular weight epoxide resins, a large excess of epichlorohydrin for each equivalent of phenol should be employed, and accordingly in the process of this invention an excess of about 5 up to about 50 mols of epichlorohydrin for each mol of total phenol reactants is used. The alkali present in the reaction mixture is preferably an alkali metal hydroxide such as sodium, potassium or lithium hydroxide, and is present in an amount sufficient to neutralize the hydrochloric acid produced during the reaction, as well as to transform the chlorohydrin formed in the initial reaction of phenol and epichlorohydrin to an epoxide-containing molecule. Preferably this amount is between about 2 mols and about 4 mols of alkali per mol of total phenolic compounds.

A method of preparing the trisphenol of this invention, i.e., oc,a',x" tris(hydroxyphenyl)-l,3,5-triisopropylbenzene, may be found described in copending U.S. application Ser. No. 392,291, filed Aug. 26, 1964 by Vitrone et al. assigned to this assignee, now abandoned, The process consists of reacting a,a,ot-trihydroxy1,3,5-triisopropylbenzene and phenol in the presence of an acidic condensation catalyst to yield the desired product. The structural formula may be represented as:

2,2-bis(p-hydroxyphenyl) propane, available commercially as Bisphenol A, may be represented as having the following structural formula:

(3H3 While the exact structural formulas of the terpolymeric epoxide resins of this invention are not known they may be represented as having the following theoretical structural formula:

wherein R ha the formula mc-o-cm CH3 R has the formula and A is selected from the group consisting of R and R, n representing a number ranging up to about 25. It is to be understood, however, that the above structural formula represents an idealized version, and its exact composition may vary depending on the reaction conditions of the process. For example, epichlorohydrin could react with the one remaining hydroxy group on the trisphenol molecule as well.

It has been found that the presence of water has a pronounced influence upon the reaction of this invention. More specifically, .it is preferred that water be present as a reaction-initiator in amount of at least 0.3% of the total weight of the reaction mixture. The amount of water preferably ranges from at least about 0.3% to about 5% of the total weight of the reaction mixture in the preparation of low molecular weight resins.

The crude reaction mixture obtained contains salts, excess alkali, unreacted epichlorohydrin, and water, all of which should be removed. This may be accomplished by dissolving the resin in a suitable aromatic solvent such as benzene, toluene, xylene, and the like, washing several times with water, and separating the aqueous and organic layers. The organic solvent is then distilled off. The resin may be further purified by dissolving in acetone, cooling to room temperature, filtering off any solid impurities, and evaporating the acetone. The final terpolymeric epoxide resin has an epoxide equivalent within the range of about 200 to about 260.

The terpolymeric epoxide resins prepared by this invention may be cured with conventional curing agents such as amines, organic polyacids and anhydrides, polyamides, Friedel -Crafts metal halides, phosphoric acid and partial esters thereof and salts of inorganic acids.

anhydride, dodecenyl succinic anhydride, tetrachlorophthalic anhydride and chloroendic anhydride;

(3) Amides having reactive amino groups.-- Dicyandiamide, polyamide resins prepared by the reaction of a dimerized or trimerized vegetable oil, unsaturated fatty acid with aryl or alkyl polyamines such as the reaction product of linoleic acid dimer with ethylene diamine;

(4) Friedel-Crafts metal ha1ides.-Aluminum chloride,

zinc chloride, ferric chloride and boron trifluoride as well i as complexes thereof with ethers, acid anhydrides, ketones, diazonium salts;

(5) Phosphoric acid and partial esters thereof.-n- Butyl dihydrogen orthophosphate, and diethyl orthophosphate;

(6) Salts of inorganic acids.Zinc fiuoborate, potassium. persulfate, nickel fluoborate, copper fluohorate, selenium fluoborate, magnesium fiuoborate, tin fiuoborate, potassium magnesium arsenate, magnesium sulfate, cadmium arsenate, cadmium silicate, aluminum fiuoborate, ferrous sulfate, ferrous silicate, manganese hypophosphite, nickel phosphate and nickel chlorate.

The preferred class of curing agents is the amino compounds. A number of these amino compounds such as diethylenetriamine and diethylamino propylamine are sufiiciently active to effect curing at room temperature and such systems can be used for adhesives and other uses where it is usually not practical to require preheating The best curing cycle must be determined for each curing agent used. When using an amine curing agent, .it is best to provide one active hydrogen for each epoxide group of the resin. Thus, when curing a resin having an epoxicle equivalent of about 200 with m-phenylene diamine, which has four active hydrogens and a molecular weight of 108, about 13.5 grams of the curing agent should be used for each grams of resin. The amount of curing agent may be varied somewhat, but the variation should not be greater than about 5%.

The epoxide resins may. be modified by reacting them with conventional epoxide modifying agents such as urea formaldehyde, phenol formaldehyde, and melamine formaldehyde. Additionally, the physical properties of the resin may be changed by dissolving therein a solid epoxide resin of higher epoxide equivalent.

The invention will be described further in conjunction with the following specific examples, but it is to 'be understood that these are merely for purposes of illustration and are not intended to limit the invention thereto.

Example '1 To a. resin flask provided with a stirrer, thermometer, condenser and heating mantle were added 0.4 mol of 2,2- bisOp-hydroxyphenyl)propane, 0.2 mol of a,a',a"-tris(hydroxyphenyl)-1,3,S-tr-iisopropylbenzene, 6.0 mols of epichlorohydrin, and 0.37 mol of water. The mixture was stirred continuously and heated to reflux. 1.54 mols of solid sodium hydroxide pellets were added slowly at such a rate as to maintain reflux temperatures but avoid excessive heat. The mixture was maintained at reflux temperatures for an additional two hours. The mixture was allowed to cool slightly and 500 ml. of benzene was added to dissolve the resin. The solution was extracted with three 300-1111. portions of deionized Water, and the aqueous layer discarded. The organic layer was distilled at 160 The resin was then poured into molds and heated at 150 C. for -6 hours. The physical properties of the resins are given in Table 1, wherein Bisphenol A is abbreviated as EPA and a,oc',oa" tris(hydroxyphenyl) 11,3,5 triisomm. of mercury pressure up to 125 C. to remove benpropylbenzene is abbreviated as tris.

TABLE I ASTM Example 1 Example 2 Example 3 BPA Epoxicle Tris Epoxide Properties Test No. TriszBPA 1:2 TriszBPA 2:1 TriszBPA 1:1 Epoxide Equivalent 216 250 231 205 258 C0lor Amber Amber Amber Amber Amber Ultimate Tensile Strength, p.s.i 638 10, 390 10, 000 10, 950 12, 500 8, 740 Ultimate Elongation, Percent... 638 8. 3 8. 3 8. O 5. 9 3.9 Flexural Modulus, p.s.i. D790 437, 160 448, 820 441, 350 435, 967 526, 316 Izos Impact, it.-lbs./in. notch 256 44 .38 .60 .62 .37 Rockwell Hardness (M) D785 124 126 104 112 Heat Distortion Temperature/264, p.s.i.

zene. The resin was dissolved in about twice its volume We claim: of acetone, the solution cooled to room temperature and 1. A curable terpolymeric epoxide resin produced by a filtered. The acetone was evaporated. The resultant resin process which comprises heating at a temperature of at had an epoxide equivalent of 216. least 75 C. a reaction mixture comprising 2,2-bis(p-hyd-roxyphenyl)-propane, from about 0.5 to about 2 mols of Example 2 0:,oc ,a tr1s(hydroxyphenyl) 1,3,5 trnsopropylbenzene The p f 0f EXample 1 Was Tfipeated 115mg for each mol of 2,2,-bis(p-hydroxyphenyl)-propane pres- H101 2 (P- y yp y )P 3 11101 of out, and from about 5 to about 50 mols of epichlorohymi Y P Y 1,3,5 7 p p drin for each mol of phenolic reactant present, in the Zfifle- The resultant Tesll'l had all epOXlde equlvalent of presence of an alkali and recovering the resultant epox- 250. ide.

Ple 3 2. An epoxide resin according to claim 1 wherein from The procedure of Example :1 was repeated using ()3 about 2 to about 4 mols of an alkah metal hydroxide 18 mol of 2,2 bis(p hydroxyphenyDpnopane and 0.3 mol Present for i P P Teactant; of cz,0c',rx" tris(hydroxyphenyl) 1,3,5 triisopro ylb 3. An epoxide resln according to claim 1 wherem the Zena The resultant resin had an epoxide equivalent of heating is conducted in the presence of at least about 0.3 percent to about 5 percent by weight of water based on Example 4 the total weight of reactants.

4. An epoxide resin according to claim 1 wherein the Cured samPles 9 the epoxlde resms of EXamPIes reaction mixture is heated at a temperature from about were compared w1th cured samples of a commerclally 40 up to its reflux temparamm available epox1de resin of Bisphenol A having an epoxide 5 A cured terpolymeric epoxide resin having a high equlYalent f 205 (Shell Company 5 Efpon 828) heat distortion temperature produced by curing the resin epoxide resln prepared from the reaction of ot,a ,OL -tr1s of claim 1 with an epoxide curing agent l {P Wlth 6. A cured terpolymeric epoxide resin having a 'high F of ePl'chlorohydnn accordmg method des cnbed heat distortion temperature produced by curing the resin in US. Ser. No. 392,291 -(above), sald resin having an of claim 1 with apolyamine curing agelm epoxide equivalent of 258.

In preparing the cured samples, the epoxide resins were Ref re e Cit first admixed with m-phenylene diamine at a temperature of about 60 C. The proper amount is calculated accord- UNITED STATES PATENTS ing to the formula:

Epoxide equivalent 3,309,339 3/1967 Barton et a1.

WILLIAM H. SHORT, Primary Examiner. T. D. KERWIN, Assistant Examiner. 

